1. Field of the Invention
The present invention generally relates to a magnetic head having an inductive-type writer and a magneto-resistive (MR) reader with the writer and the reader being supported by a substrate in a stacked fashion. More particularly, the present invention relates to a magnetic head having an inductive-type writer, an anisotropic magneto-resistive (AMR) reader, and a giant magneto-resistive (GMR) reader with the writer, the AMR reader, and the GMR reader being supported by a substrate in a stacked fashion.
2. Background Art
Magnetic heads have writers to write data onto magnetic media such as magnetic tape or any other removable magnetic storage media. The writers generate magnetic flux for recording magnetic transitions into the media in order to write data onto the media. Magnetic heads have readers to read data from the media. The readers sense magnetic flux from the magnetic transitions recorded in the media in order to read data from the media.
Certain magnetic heads have an inductive-type writer and a magneto-resistive (MR) reader in which the writer and the reader are supported by a substrate in a stacked fashion. The reader is typically either an anisotropic magneto-resistive (AMR) reader or a giant magneto-resistive (GMR) reader. That is, some magnetic heads have an inductive-type writer and an AMR reader whereas other magnetic heads have an inductive-type writer and a GMR reader.
Compared with AMR readers, GMR readers are more sensitive and are tuned for thinner media with less magnetic flux which allows a higher linear recording density. As such, AMR readers are used to read data from higher flux media whereas GMR readers are used to read data from lower flux media capable of higher linear recording densities.
It is a problem when AMR readers are used to read data from lower flux media. This is a problem because AMR readers are not sensitive enough to read the lower flux media. Likewise, it is a problem when GMR readers are used to read data from higher flux media. This is a problem because GMR readers are too sensitive to read the higher flux media and become saturated when reading higher flux media.
In the past, the prevalent MR reader used in magnetic heads for tape applications was the AMR reader and the prevalent media was the higher flux media. In the future, it is expected that the prevalent MR reader to be used in magnetic heads for tape applications will be the GMR reader. Correspondingly, lower flux media capable of higher linear recording densities will be provided for use with the GMR reader.
As a result of the problems associated with AMR and GMR readers, backward compatibility between higher flux AMR readers optimized for lower recording densities and lower flux GMR readers optimized for higher recording densities is expected to be a problem. Backward compatibility is a problem because GMR readers are not able to read data from higher flux media which was prevalent in the past whereas AMR readers are not able to read data from lower flux media which is expected to be prevalent in the future.